Whilst there are many sources of data relating to ‘Earth’s Energy Budget’, these quantities and values of solar radiation and its various pathways enabling absorption, emission and reflection to and from the earth’s surface are quantified in Watts/m2 and therefore do not necessarily provide a good indication of ‘actual’ energy values over time when comparing these values against themselves or other sources of energy within the system.

Alternatively, utilising the joule standard of energy measurement over a period of time provides a good context for measurement and comparison of such solar and waste heat energy sources as well as quantifying additional stored heat in relation to this ‘Energy Budget’.

Whilst analysis of solar radiation entering and exiting the Earth system has been the subject of significant work over decades and therefore well documented, analysis of Anthropogenic Waste Heat (AWH) from human activities has received much less interest. The main reason for this is because it appears a relatively low value compared to solar radiation and therefore generally deemed of little or no consequence in terms of it’s effect in the environment.

Because of this, there is no ‘off the shelf’ AWH data available and therefore much of this data requires extraction from other sources combined with some critical ‘interpretation’ and ‘assumption’.

I have compiled a basic analysis of AWH based on the three main heat sources listed below – although have not including additional human related effects such as wildfires and small but increasing geothermal sources etc for simplicity:

  1. Hydrocarbon Fuel Combustion
  2. Carbohydrate Fuel (food) Combustion
  3. Nuclear Power Production

I have utilised data from ‘our world in data’ in respect of annual Hydrocarbon and Nuclear power consumption (however, Nuclear Power is based on electricity generated and so I have compensated 40% to account for heat losses during the steam based generating process). I believe that 100% of heat capacity from these other sources eventually enters the environment (regardless of work) and so there is no discount in this respect contrary to some climate models. I have calculated the heat emissions from humans only (not livestock) in respect of Carbohydrate combustion which I have reduced from the generally accepted average of 120W to 100W per person to allow for the younger population which is likely to be physically smaller. The current human population is 8 Billion, therefore 8 Billion@100W = 7,008 TWh/annum.

The solar radiation quantities are taken from the graph below used by American Meteorological Society although these same figures are also generally used by most recognised global institutions such as NASA, IPPC etc.

Other data used including ‘Earth’s Surface Area’ are widely available and universally accepted. These values are shown with the calculations.

  1. Hydrocarbon combustion per annum =  140,000TWh = 0.504 Zettajoules
  2. Carbohydrate combustion per annum =    7,008 TWh = 0.025 Zettajoules
  3. Nuclear Power Consumption per annum = 3,640 TWh = 0.013 Zettajoules


Total AWH per annum                                                          0.542 Zettajoules

Surface Area of Earth         =           510,000,000,000,000 m2 = (510×10/12) m2

Total AWH relative to Earth’s surface                                              0.033 W/m2

Solar radiation absorbed by earth’s surface + atmosphere         =     240W/m2

240w/m2                                         =      7568640000 (7.56×10/9)  J/m2/annum

Total Solar per annum = (510×10/12)x(7.56×10/9)=(3860×10/21)3860 Zettajoules

*Solar radiation absorbed by earth’s surface only                        =         160W/m2

*Total Solar per annum=(510×10/12)x(5.04×10/9)=(2573×10/21)2573 Zettajoules


*As AWH is generally delivered at or just above earth’s surface it could be considered that when comparing AWH to solar radiation it may be appropriate to compare only solar radiation absorbed by earth’s surface and so I have included both the combined surface and atmospheric solar absorption figure along with the earth ‘surface only’ solar absorption figure for reference. Below indicates AWH as fractions of these two quantities.

AWH relative to total surface + atmosphere solar rad   = 3860/0.542  =  1:7121

AWH relative to earth surface solar radiation only        =  2573/0.542  =  1:4747


The Earth Energy Budget increase is considered to be 0.9W/m2 which is mostly stored in ocean heat causing a current increase of 14 Zettajoules/annum. Comparing this net budget with AWH provides the fraction below which indicates that Earth’s total warming is just 27 x’s greater than AWH.

Energy Budget (0.9W/m2) / AWH (0.033W/m2)                                    =  1:27

These above figures and comparisons demonstrate that although AWH is substantially lower than absorbed solar radiation, it remains significant – and being introduced at earth’s surface as direct kinetic energy and long wave infrared radiation may also have other influencing effects. Furthermore, dismissal of AWH as being ‘insignificant’ does not compliment the existing belief that CO2 is ‘significant’. This can be demonstrated by fractional comparison of increases in atmospheric CO2 (150ppm) which is 1:6666 compared to the fractional comparison of AWH to net heating 1:27 (as explained above) over the same post-industrial time period?

Could AWH and water vapour (not CO2) be dominating climate change?


Phil Selwyn CEO/Founder (Water Powered Technologies)      15/10/23